In gas turbine engines of the type in which the present concepts were developed, working medium gases are compressed within a compression section and used as an oxidizing agent in the production of a high temperature effluent. The high temperature effluent is subsequently expanded through a turbine section. Within the turbine section blades extend outwardly across the flowpath for working medium gases to extract energy from the gases flowing thereacross. The temperature of the working medium gases flowing through the turbine section in modern engines is on the order of and may even locally exceed twenty-five hundred degrees Fahrenheit (2500.degree. F.). Limiting the temperature of the metal from which the blades are fabricated is extremely critical in order to preserve material strength in the face of high centrifugal loads and to prevent local material deterioration.
The source of cooling air for the rotor blades is the compression section of the engine. High pressure relatively cooled gases are flowed through the interior of the engine to the region of the turbine rotor section and radially outwardly to the rim region of the disk for distribution to the individual rotor blades. U.S. Pat. Nos. 3,728,042 to Hugoson et al entitled "Axial Positioner and Seal for Cooled Rotor Blade"; 3,814,539 to Klompas entitled "Rotor Sealing Arrangement for an Axial Flow Fluid Turbine"; 3,853,425 to Scalzo et al entitled "Turbine Rotor Blade Cooling and Sealing System"; 4,213,738 to Williams entitled "Cooling Air Control Valve"; and 4,236,869 to Laurello entitled "Gas Turbine Engine Having Bleed Apparatus with Dynamic Pressure Recovery" are representative of the myriad of technical concepts employed in the distribution of cooling air to the rotor blades. In each of the above constructions a chamber for distribution of cooling air is formed between a blade supporting disk and adjacent structure affixed thereto.
Notwithstanding the availability of these concepts and others described in literature, scientists and engineers continue to search for techniques capable of judiciously distributing cooling air to the rotor blades.